The EPA announced new drinking water health advisory levels today for the industrial chemicals PFOA and PFOS. The new levels — .07 parts per billion (ppb) for both chemicals — are significantly lower than standards the agency issued in 2009, which were .4 ppb for PFOA and .2 ppb for PFOS. In areas where both PFOA and PFOS are present, the advisory suggests a maximum combined level of .07 ppb. While the old levels were calculated based on the assumption that people were drinking the contaminants only for weeks or months, the new standards assume lifetime exposure and reflect more recent research.

The new federal standards may unify what has been an inconsistent official response to the presence of these perfluorinated chemicals, or PFCs, in drinking water. They will also instantaneously create official water contamination crises in dozens of cities and towns across the country.

According to the EPA’s most recent data on unregulated drinking water contaminants, released in January, 14 drinking water systems around the country reported levels of PFOA that exceed the new federal threshold, while 40 reported PFOS above the new cutoff. In all, water systems in 18 states, as well as in Guam, are contaminated.

Some of these water systems have already begun to quietly address the problem. In Suffolk County, New York, where public drinking water wells show PFOS levels of .33 and .53 ppb, the contaminated water “has either been blended with other wells to reduce the level of the compound to non-detection or their use has been limited to the greatest extent possible,” according to Kevin Durk, director of water quality and laboratory services for the Suffolk County Water Authority. Though he does not know the level of PFOS in the water that comes out of local taps, Durk wrote in an email that “it is a virtual certainty that levels of any detected chemical would have been reduced.”

Similarly, the Security Water and Sanitation District in Colorado Springs has been struggling to clean up its contaminated water since 142 tests detected PFCs. The district has shut down seven out of 26 wells and is blending water to lower levels, according to Roy Heald, the district’s general manager.

But other water company operators have yet to lower their PFC levels. Steve Anderson, owner of the Oatman Water Company in Scottsdale, Arizona, where PFOS measured .2 and .23 in the most recent EPA testing, learned that the chemical was in his water only recently, after he received a call from the Arizona Department of Environmental Quality. Anderson, who suspects the PFOS originated from firefighting foam used by the nearby Oatman Fire Department, said he is “trying to come up with a solution.”

Until today, there was a wide range of official opinion on the level of contamination that presented a health danger. The military, which is in the throes of a massive cleanup of 664 contaminated fire- and crash-training sites, has been using the EPA’s older standards for PFOA and PFOS to guide its efforts and help determine who receives clean drinking water and remediation of contaminated private wells. (The Department of Defense did not responded to inquiries about how the new advisory levels would alter its cleanup plan.)

Others have set more stringent standards. On January 28, the EPA advised residents of Hoosick Falls, New York, not to use water with PFOA levels above .1 ppb. And a panel of scientists who spent years researching some 70,000 people whose water contained PFOA levels of at least .05 ppb, found probable links between that level of exposure and testicular cancer, kidney cancer, thyroid disease, preeclampsia, ulcerative colitis and high cholesterol. In 2010, New Jersey’s Drinking Water Quality Institute calculated a safety limit of .04 for PFOA. Vermont currently has the lowest state drinking water limit for PFOA, .02 ppb.

The EPA report noted that in humans “the developing fetus and newborn is particularly sensitive to PFOA-induced toxicity.”

The report also acknowledged research on human populations that has found associations between PFOS and immune suppression, thyroid disease, high cholesterol, and reduced fertility. It also acknowledged a possible connection between PFOS and bladder, colon, and prostate cancer.

The new health advisory for PFOA was also based on human studies, which showed “associations between PFOA exposure and high cholesterol, increased liver enzymes, decreased vaccination response, thyroid disorders, pregnancy-induced hypertension and preeclampsia, and cancer (testicular and kidney).” The EPA report noted that in humans “the developing fetus and newborn is particularly sensitive to PFOA-induced toxicity.”

“Taken together,” the report notes, “the weight of evidence for human studies supports the conclusion that PFOA exposure is a human health hazard.” The exact phrasing was used in the PFOS report as well.

While calling the new level “a very long-overdue step in the right direction,” Robert Bilott, an attorney overseeing a class-action suit over PFOA contamination near a DuPont plant in West Virginia, cautioned that “the new guideline is still too high, as exposures at even the new guideline level would allow PFOA to continue to build up to ever-increasing, unacceptable levels in human blood.”

Bilott also noted that the new levels are informal guidelines, as opposed to enforceable regulatory limits. “If it was enforceable,” he said, “the EPA could issue unilateral orders requiring the responsible party to clean it up.”

Updated May 19, 2016:

After this piece was published a spokesperson for the Department of Defense wrote in an email that “DoD will use the EPA’s new Health Advisory levels to determine risk to human health from past contamination. DoD’s approach is comprehensive and designed to identify where we have had releases of PFOA or PFOS and to determine if the release has impacted drinking water above the Environmental Protection Agency’s Health Advisory level. Where that has happened DoD will work closely with the regulatory agencies and the local community to provide alternative drinking water supplies.”